1. Field of the Invention
The present invention relates to a mobile phone, and more particularly to a mobile phone with a power saving function.
2. Description of the Related Art
A recent mobile phone has various functions in addition to an original communication function. For example, a mobile phone is used widely which has application functions such as a schedule managing function, a calculator function, a musical reproducing function, a game function, an alarm (awaking) function, and a digital camera function. In such a mobile phone, a call waiting function is operating while any application function other than the communication function is used.
There is a case that the mobile phone is carried in a travel, because the above-mentioned application functions are provided for the mobile phone. However, when any base station does not exist for the mobile phone, the mobile phone always tries to communicate with the base station at the maximum transmission power. As a result, there is a possibility that a battery is consumed and the time period during which the application function of the mobile phone can be used becomes short extremely. The power consumption of the battery can be avoided, even if the power is turned on only for the use of the application function and the power is turned off after the use. However, during the use of the alarm (awaking) function, the power supply cannot be switched off.
As the power saving function of the mobile phone, a method is known in which the power supply is switched off while a call signal to a mobile phone other than the mobile phone of a user is received, as disclosed in Japanese Laid Open Patent Application (JP-A-Showa 57-54442). According to this method, the call signal to the mobile phone of the user is used as a trigger and the power supply of the mobile phone is switched off until the reception of call signal. Also, a method is known in which all the reception operations are stopped for a predetermined time when input electric field becomes continuously lower than a predetermined level in the receiving operation, as disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 4-355524).
In the above-mentioned conventional techniques, it is necessary to carry out the reception of the call signal intermittently. Therefore, it is impossible to switch off the power supply continuously. Also, in the above-mentioned conventional techniques, there is no description about the mobile phone with the application functions other than the communication function. The measure to the above-mentioned situation is not considered.
In conjunction with the above description, a cordless telephone apparatus is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 6-69854). The codeless telephone apparatus of this conventional example consists of a parent apparatus connected with a telephone line in a wire, and a child apparatus connected with the telephone line through the parent apparatus to which is connected in a radio channel. The child apparatus has a battery, and receives a control signal from the parent apparatus intermittently such that the connection and disconnection of the battery is controlled. The child apparatus contains a plurality of period generation sections generating a plurality of intermittent reception periods. A period selection section selects one of the period generation sections for a necessary intermittent reception period. A microcomputer controls all kinds of operations of the child apparatus. The child apparatus further contains a switch to inform the stop of the reception from the parent apparatus to the microcomputer, and a timer as a 24-hour timer. A switching time storage section stores a time for the period generation section to be switched, a time for the operation to be switched from the intermittent reception from the parent apparatus to the receiving operation stop, or a time for the operation to be switched from the receiving operation stop to the intermittent reception from the parent apparatus. In the child apparatus, in case that the reception is not stopped, the period selection section selects one of the period generation sections based on a time measured by the timer and the switching time stored in the switching time memory to switch into the intermittent reception period. In case that the reception is stopped, the period selection section selects one of the period generation sections based on a time measured by the timer and the switching time stored in the switching time memory to switch from the intermittent reception operation into the reception stop operation.
Also, a cordless telephone apparatus is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 6-112889). This conventional example is composed of a plurality of parent apparatuses and child apparatuses. While the child apparatus is in a call waiting state, a control unit does not carry out confirmation of an area of the child apparatus through the parent apparatuses. While the child apparatus is in a communication state, the control unit changes the parent apparatuses from one into another in accordance with a reception level of a communication channel.
Also, a variable intermittent reception system in a mobile communication is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 7-131404). A mobile terminal of this conventional example is composed of a radio receiving section, a timing generating section which generating a timing signal for the receiving operation of the radio receiving section, a memory which stores a scheduled time, a timer, and a control unit. When the timer indicates the scheduled time, the control unit controls the timing generating section such that an intermittent reception ratio is increased.
Also, a mobile communication system with an emergency signal transmitting and receiving function is disclosed in Japanese Laid Open Patent Application (JP-P2002-9686A). This conventional example is relates to a mobile communication system of a mobile phone of a PDC method, various CDMA methods and a mobile terminal of PHS. The mobile terminal has an emergency signal transmission section which sends an emergency signal through an operation of the mobile terminal when the mobile terminal is in a communication area of a base station and is not in the communication area thereof. The base station has an emergency signal response processor which receives the emergency signal from the mobile terminal and notifies to a center which has an urgent time mobile terminal situation display section which receives the emergency signal from the base station and displays the contents of the emergency signal and specifies the position of the mobile terminal. A moving base station has a center having a terminal situation display mechanical section which receives the emergency signal, and displays the contents of the emergency signal and specifies the position of the mobile terminal.
Also, a method of switching to a power saving mode in a radio communication system is disclosed in Japanese Laid Open Patent Application (JP-P2002-158609A). In this conventional example, a TDMA radio communication system is composed of a base station and a plurality of terminal stations. The base station transmits a power saving mode switching instruction to the plurality of terminal stations. Each of the terminal stations receives the power saving mode switching instruction and changes into an intermittent reception operation, after transmitting the state of the terminal station and confirmation of the reception of the switching instruction to the base station. When receiving the state of the terminal station and confirmation of the reception of the switching instruction from each of the terminal stations, the base station changes from a continuation transmission operation of information into an intermittent transmission operation and into an intermittent reception operation.